This invention pertains to tools for the removal of a single pin form a high density matrix of pins presented by an electrical connector and more particularly to a tool for the backside removal of a single pin that is effective to remove compliant pins.
The use of high density connectors with closely spaced rows and columns of connector pins and especially those with compliant connector pins, brings the requirement that highly populated connectors be repairable to reclaim such complex and expensive devices by the replacement of one or a few damaged pins. The removal of a single connector pin is not difficult in a low pin density connector which can tolerate the use of a simple tool such as long nose pliers to clamp about and seize a pin for extraction. Many common extraction devices seize a pin or grasp a pin behind an enlarged portion to allow the pin to be pulled out in unison with the extracting tool. Another approach is the use of a tool with the jaws of a chuck that are positioned around the pin and constricted by a sleeve or other means to capture the pin. None of these devices or techniques have been found effective for the removal of pins where the center to center spacing of adjacent pins is about 2 millimeter and the space between adjoining pin surfaces is no more than 1 millimeter. In such an environment, it is difficult to remove one pin without damaging one or more adjacent pins.
Even where a device or tool is capable of extracting a pin from a high density pin matrix, it is useless if the reason for replacement is that the pin is broken off or missing making it impossible to seize and pull out the pin. When only the compliant pin portion extending from the back side of the connector is available, it is necessary to have a tool that is capable of driving the pin from the connector. Further, since compliant pin connectors are commonly not reliably removed and reinstalled, it is necessary that a tool for the backside removal of a single pin be capable of removing a pin from either the uninstalled connector or from an installed connector having the compliant connector portions received in the plated vias of a host device such as a printed circuit board.
The pin removal tool of the present invention includes a thin wall sleeve that can be received about a pin in a high density matrix of pin rows and columns, without compromising an adjacent pin. With the sleeve advanced to surround the pin and abut the connector body, a shaft, which is substantially the same diameter as the inner wall of the sleeve, is advanced through the sleeve to engage the surrounded pin and drive it from the connector body wall portion through which it extends. To assure that the shaft does not become wedged between the pin and the sleeve, the shaft end surface is concave, presenting a substantially hemispherically recessed surface which engages and aligns the pin allowing a substantially axial force to be applied to the pin.
The same tool is effective when the connector is installed with the compliant connector portions resident in plated through vias formed in a printed circuit board or other host device. In this environment, the sleeve is aligned with the via from which the pin is to be removed with the precise final alignment achieved when the shaft end is received in the via opening. With the sleeve end surface abutting the host printed circuit board, the shaft is advance through the via to drive the pin from the via and permit final withdrawal from the front side. In this environment, the walls forming the via provide radial confinement of the pin as the shaft is advanced during pin removal.